deb-substvars - Debian source substitution variables
debian/substvars,
debian/binary-package.substvars,
variables
Before
dpkg-source,
dpkg-gencontrol and
dpkg-genchanges
write their control information (to the source control file
.dsc for
dpkg-source and to standard output for
dpkg-gencontrol and
dpkg-genchanges) they perform some variable substitutions on the output
file.
A variable substitution has the form
${variable-name}.
Variable names consist of alphanumerics (a-zA-Z0-9), hyphens (-) and colons
(:) and start with an alphanumeric, and are case-sensitive, even though they
might refer to other entities which are case-preserving. Variable
substitutions are performed repeatedly until none are left; the full text of
the field after the substitution is rescanned to look for more substitutions.
Substitution variables can be specified in a file. These files consist of lines
of the form
name=value or
name?=value. The
= operator assigns a normal
substitution variable, while the
?= operator (since dpkg 1.21.8)
assigns an optional substitution variable which will emit no warnings even if
unused. Trailing whitespace on each line, blank lines, and lines starting with
a
# symbol (comments) are ignored.
Variables can be set using the
-V common option. They can be also
specified in the file
debian/substvars (or whatever other file is
specified using the
-T common option).
After all the substitutions have been done each occurrence of the string
${} (which is not an actual substitution variable) is replaced with a
$ sign. This can be used as an escape sequence such as
${}{VARIABLE } which will end up as
${VARIABLE } on the output.
If a variable is referred to but not defined it generates a warning and an empty
value is assumed.
While variable substitution is done on all control fields, some of those fields
are used and needed during the build when the substitution did not yet occur.
That's why you can't use variables in the
Package,
Source and
Architecture fields.
Variable substitution happens on the content of the fields after they have been
parsed, thus if you want a variable to expand over multiple lines you do not
have to include a space after the newline. This is done implicitly when the
field is output. For example, if the variable
${Description} is set to
"foo is bar.${Newline}foo is great." and if you have the following
field:
Description: foo application
${Description}
.
More text.
It will result in:
Description: foo application
foo is bar.
foo is great.
.
More text.
Additionally, the following standard variables are always available:
- Arch
- The current host architecture (i.e. the architecture the
package is being built for, the equivalent of DEB_HOST_ARCH).
- vendor:Name
- The current vendor name (since dpkg 1.20.0). This value
comes from the Vendor field for the current vendor's origin file,
as dpkg-vendor(1) would retrieve it.
- vendor:Id
- The current vendor ID (since dpkg 1.20.0). This is just the
lowercase variant of vendor:Name.
- source:Version
- The source package version (since dpkg 1.13.19).
- source:Upstream-Version
- The upstream source package version, including the Debian
version epoch if any (since dpkg 1.13.19).
- binary:Version
- The binary package version (which may differ from
source:Version in a binNMU for example; since dpkg 1.13.19).
- Source-Version
- The source package version (from the changelog file). This
variable is now obsolete and emits an error when used as its
meaning is different from its function, please use the
source:Version or binary:Version as appropriate.
- source:Synopsis
- The source package synopsis, extracted from the source
stanza Description field, if it exists (since dpkg 1.19.0).
- source:Extended-Description
- The source package extended description, extracted from the
source stanza Description field, if it exists (since dpkg
1.19.0).
- Installed-Size
- The approximate total size of the package's installed
files. This value is copied into the corresponding control file field;
setting it will modify the value of that field. If this variable is not
set dpkg-gencontrol will compute the default value by accumulating
the size of each regular file and symlink rounded to 1 KiB used units, and
a baseline of 1 KiB for any other filesystem object type. With hardlinks
only being counted once as a regular file.
Note: Take into account that this can only ever be an approximation,
as the actual size used on the installed system will depend greatly on the
filesystem used and its parameters, which might end up using either more
or less space than the specified in this field.
- Extra-Size
- Additional disk space used when the package is installed.
If this variable is set its value is added to that of the
Installed-Size variable (whether set explicitly or using the
default value) before it is copied into the Installed-Size control
file field.
-
S:fieldname
- The value of the source stanza field fieldname
(which must be given in the canonical capitalization; since dpkg 1.18.11).
Setting these variables has no effect other than on places where they are
expanded explicitly. These variables are only available when generating
binary control files.
-
F:fieldname
- The value of the output field fieldname (which must
be given in the canonical capitalization). Setting these variables has no
effect other than on places where they are expanded explicitly.
- Format
- The .changes file format version generated by this
version of the source packaging scripts. If you set this variable the
contents of the Format field in the .changes file will
change too.
-
Newline, Space, Tab
- These variables each hold the corresponding character.
-
shlibs:dependencyfield
- Variable settings with names of this form are generated by
dpkg-shlibdeps.
- dpkg:Upstream-Version
- The upstream version of dpkg (since dpkg 1.13.19).
- dpkg:Version
- The full version of dpkg (since dpkg 1.13.19).
- debian/substvars
- List of substitution variables and values.
dpkg(1),
dpkg-vendor(1),
dpkg-genchanges(1),
dpkg-gencontrol(1),
dpkg-shlibdeps(1),
dpkg-source(1).